There is an ongoing need for solid state circuits adapted to operate at higher and higher frequencies, including microwave frequencies. As used herein, the term “microwave” is intended to refer to frequencies at or above about 300 MHz, for example between 300 MHz and 3 GHz. Various transistor structures have been created that are capable of providing gain in such frequency ranges. A LDMOS (Lateral Diffused Metal Oxide Semiconductor) transistor is an example of such a transistor structure.
For power amplifier circuits with a faster switching speeds, LDMOS transistors with a high breakdown voltage and low on-resistance are desirable. However, these parameters are influenced in an opposing manner. For example by increasing the drift length, the breakdown voltage is improved but the on-resistance is increased.
Therefore, further improvements to provide transistor devices with improved performance at higher frequencies are desirable.